Oops. Fix make variable name. Thanks again, make.

Change-Id: Iecbb41acc835bb8eb20b668c89a3ff065470fcb7
diff --git a/adb_listeners.c b/adb_listeners.c
index 76a03eb..699f3f5 100644
--- a/adb_listeners.c
+++ b/adb_listeners.c
@@ -16,6 +16,8 @@
 
 #include "adb_listeners.h"
 
+#include <stdio.h>
+
 #include "sysdeps.h"
 
 int gListenAll = 0; /* Not static because it is used in commandline.c. */